When Prince called into George Lopez's "Lopez Tonight" TV show in early April and announced that in less than a week he'd play the Inglewood Forum to kick off a string of 21 concerts in the region, some of his staunchest fans wondered whether he'd bitten off more than even he could chew.

The enigmatic singer, guitarist, songwriter, producer and entrepreneur is on track to wrap up his extended L.A.-area run imminently, having played 19 concerts at the 18,000-capacity sports arena, plus two smaller-scale evenings with multiple shows each night at the Troubadour and House of Blues clubs in West Hollywood. And he had enough energy left over to sandwich in three Northern California arena dates last week.

FOR THE RECORD: Prince: An article in the June 2 Calendar section about Prince's multiple-night stand at the Forum in Inglewood referred to the church that purchased the arena in 2000 as the Faith Central Bible Church. It is the Faithful Central Bible Church. —

The long engagement has ramped up excitement about Prince at a time when he has no new album to sell, gets little to no radio airplay except on oldies and classic-rock radio stations and no movie, TV show or book to plug. Shows have been announced one weekend at a time, usually only a few days before they occurred; for his House of Blues drop-in, where he played three sets in three different parts of the facility, tickets went on sale the day before; ticket buyers didn't learn the location until the day of the show. Details on the final round of shows still had not been announced as of early Wednesday afternoon.

"Prince walks, eats, sleeps and breathes to his own drum, and in his case it's a complete rhythm section," said Randy Philips, CEO of AEG Live, the co-promoter of his 21-night stand at London's O2 arena in 2007. This run of shows is being handled by AEG competitor Live Nation. "He has earned the right through his musical genius and success and cultural impact to do things the way he wants to do them.

"That can make it hard on those of us at AEG Live, Live Nation or anybody who has a traditional business model to follow him sometimes," Philips added. "Things like that in more traditional business models can drive you completely crazy trying to keep up with him."

But Prince has kept fans buzzing online and elsewhere in recent weeks with a parade of guest artists and drastically revamped set lists from night to night, factors that have rewarded those who have taken in multiple shows. He also made repeat visits financially feasible for a broad spectrum of concert-goers by pricing 85% of the seats at each Forum show for $25.

"Doing these shows at the last minute certainly has some drawbacks in terms of being able to maximize what you can sell," said Gary Bongiovanni, editor of the concert industry-tracking publication Pollstar. "But he's obviously not that concerned with wanting to sell out every show…. It's like he's stated to his L.A. fans, 'If you want to see me, it's not going to be that hard.' … I can't think of another situation where somebody's done that many shows on a spur-of-the-moment planning basis like this."

There have been reports of a high percentage of empty seats at some shows. One concert industry veteran not affiliated with the Forum shows said attendance has been as low as 6,000 some nights, 10,000 for others, but estimated that probably at least half of the potential 350,000 tickets have been sold. Precise figures, however, aren't available. Prince declined to be interviewed for this story, as did Live Nation officials.

A key part of his strategy for sustaining public interest during the last seven weeks has been a parade of musical guests such as Stevie Wonder, Alicia Keys, Mary J. Blige, Gwen Stefani, Whitney Houston, Chaka Khan, Missy Elliott, Esperanza Spalding, Janelle Monae and Faith Evans.

"Prince has always performed live with a great backing band," said Dale Kawashima, a music publisher who worked for Prince in the 1980s and '90s and who said he attended two of the recent Forum shows as a longtime fan rather than as a former business associate. "The other thing is each night he's had some great opening act. The second night I went he had Esperanza Spalding and she did a 45-minute show before Prince went on, and that's all for $25. He puts on a big, well-produced show, he's in prime form with a great band, and you also get a set by the Grammy best new artist winner? It's unheard of."

Celebrity attendees, many of whom have popped on the Forum stage to dance or simply to glad-hand the star, have included Halle Berry, Cuba Gooding Jr., Nicole Scherzinger, Kirstie Alley and Stefani's rock star husband, Bush frontman Gavin Rossdale.

Prince has treated the Forum stand like a gargantuan bar gig, supplementing his own hit-rich catalog with a vast array of other artists' songs.

The engagement also has a philanthropic component: Prince has said he will donate some of the proceeds to the Faith Central Baptist Church, which bought the arena in 2000 and has been struggling to get out from under millions of dollars in debt from years of unprofitable operations. (Church officials are hopeful that a pending sale of the Forum to Madison Square Garden Entertainment will help ease or eliminate their financial burden.)

"He likes to find ways to call attention to himself and he loves to perform live, so this is totally consistent with his MO," said Jon Bream, author of the 1984 biography "Prince: Inside the Purple Reign." ""He's given away two albums in British newspapers. He gave away the 'Musicology' album as part of the ticket price for people who went to those [2004] shows."

Figuring out a way to play multiple dates in a single city makes considerable business sense too, as fuel prices have skyrocketed over the last year.

"It's significantly cheaper than having trucks running on the highway from market to market," AEG's Phillips said. "You can cut costs down enough to lower [ticket price] scaling, which is a good trend. The consumer perceives tremendous value for the money. Think about it: $25 at some concerts is the surcharge on the tickets."